// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <vector>

#include "base/command_line.h"
#include "base/logging.h"
#include "base/path_service.h"
#include "base/threading/thread_restrictions.h"
#include "build/build_config.h"
#include "ui/gl/gl_bindings.h"
#include "ui/gl/gl_context_stub_with_extensions.h"
#include "ui/gl/gl_egl_api_implementation.h"
#include "ui/gl/gl_gl_api_implementation.h"
#include "ui/gl/gl_glx_api_implementation.h"
#include "ui/gl/gl_implementation.h"
#include "ui/gl/gl_implementation_osmesa.h"
#include "ui/gl/gl_osmesa_api_implementation.h"
#include "ui/gl/gl_switches.h"

namespace gfx {
namespace {

    // TODO(piman): it should be Desktop GL marshalling from double to float. Today
    // on native GLES, we do float->double->float.
    void GL_BINDING_CALL MarshalClearDepthToClearDepthf(GLclampd depth)
    {
        glClearDepthf(static_cast<GLclampf>(depth));
    }

    void GL_BINDING_CALL MarshalDepthRangeToDepthRangef(GLclampd z_near,
        GLclampd z_far)
    {
        glDepthRangef(static_cast<GLclampf>(z_near), static_cast<GLclampf>(z_far));
    }

#if defined(OS_OPENBSD)
    const char kGLLibraryName[] = "libGL.so";
#else
    const char kGLLibraryName[] = "libGL.so.1";
#endif

    const char kGLESv2LibraryName[] = "libGLESv2.so.2";
    const char kEGLLibraryName[] = "libEGL.so.1";

    const char kGLESv2ANGLELibraryName[] = "libGLESv2.so";
    const char kEGLANGLELibraryName[] = "libEGL.so";

} // namespace

void GetAllowedGLImplementations(std::vector<GLImplementation>* impls)
{
    impls->push_back(kGLImplementationDesktopGL);
    impls->push_back(kGLImplementationEGLGLES2);
    impls->push_back(kGLImplementationOSMesaGL);
}

bool InitializeStaticGLBindings(GLImplementation implementation)
{
    // Prevent reinitialization with a different implementation. Once the gpu
    // unit tests have initialized with kGLImplementationMock, we don't want to
    // later switch to another GL implementation.
    DCHECK_EQ(kGLImplementationNone, GetGLImplementation());

    // Allow the main thread or another to initialize these bindings
    // after instituting restrictions on I/O. Going forward they will
    // likely be used in the browser process on most platforms. The
    // one-time initialization cost is small, between 2 and 5 ms.
    base::ThreadRestrictions::ScopedAllowIO allow_io;

    switch (implementation) {
    case kGLImplementationOSMesaGL:
        return InitializeStaticGLBindingsOSMesaGL();
    case kGLImplementationDesktopGL: {
        base::NativeLibrary library = NULL;
        const base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();

        if (command_line->HasSwitch(switches::kTestGLLib))
            library = LoadLibraryAndPrintError(
                command_line->GetSwitchValueASCII(switches::kTestGLLib).c_str());

        if (!library) {
            library = LoadLibraryAndPrintError(kGLLibraryName);
        }

        if (!library)
            return false;

        GLGetProcAddressProc get_proc_address = reinterpret_cast<GLGetProcAddressProc>(
            base::GetFunctionPointerFromNativeLibrary(
                library, "glXGetProcAddress"));
        if (!get_proc_address) {
            LOG(ERROR) << "glxGetProcAddress not found.";
            base::UnloadNativeLibrary(library);
            return false;
        }

        SetGLGetProcAddressProc(get_proc_address);
        AddGLNativeLibrary(library);
        SetGLImplementation(kGLImplementationDesktopGL);

        InitializeStaticGLBindingsGL();
        InitializeStaticGLBindingsGLX();
        break;
    }
    case kGLImplementationEGLGLES2: {
        base::FilePath glesv2_path(kGLESv2LibraryName);
        base::FilePath egl_path(kEGLLibraryName);

        const base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
        if (command_line->GetSwitchValueASCII(switches::kUseGL) == kGLImplementationANGLEName) {
            base::FilePath module_path;
            if (!PathService::Get(base::DIR_MODULE, &module_path))
                return false;

            glesv2_path = module_path.Append(kGLESv2ANGLELibraryName);
            egl_path = module_path.Append(kEGLANGLELibraryName);
        }

        base::NativeLibrary gles_library = LoadLibraryAndPrintError(glesv2_path);
        if (!gles_library)
            return false;
        base::NativeLibrary egl_library = LoadLibraryAndPrintError(egl_path);
        if (!egl_library) {
            base::UnloadNativeLibrary(gles_library);
            return false;
        }

        GLGetProcAddressProc get_proc_address = reinterpret_cast<GLGetProcAddressProc>(
            base::GetFunctionPointerFromNativeLibrary(
                egl_library, "eglGetProcAddress"));
        if (!get_proc_address) {
            LOG(ERROR) << "eglGetProcAddress not found.";
            base::UnloadNativeLibrary(egl_library);
            base::UnloadNativeLibrary(gles_library);
            return false;
        }

        SetGLGetProcAddressProc(get_proc_address);
        AddGLNativeLibrary(egl_library);
        AddGLNativeLibrary(gles_library);
        SetGLImplementation(kGLImplementationEGLGLES2);

        InitializeStaticGLBindingsGL();
        InitializeStaticGLBindingsEGL();

        // These two functions take single precision float rather than double
        // precision float parameters in GLES.
        ::gfx::g_driver_gl.fn.glClearDepthFn = MarshalClearDepthToClearDepthf;
        ::gfx::g_driver_gl.fn.glDepthRangeFn = MarshalDepthRangeToDepthRangef;
        break;
    }
    case kGLImplementationMockGL: {
        SetGLImplementation(kGLImplementationMockGL);
        InitializeStaticGLBindingsGL();
        break;
    }
    default:
        return false;
    }

    return true;
}

bool InitializeDynamicGLBindings(GLImplementation implementation,
    GLContext* context)
{
    switch (implementation) {
    case kGLImplementationOSMesaGL:
    case kGLImplementationDesktopGL:
    case kGLImplementationEGLGLES2:
        InitializeDynamicGLBindingsGL(context);
        break;
    case kGLImplementationMockGL:
        if (!context) {
            scoped_refptr<GLContextStubWithExtensions> mock_context(
                new GLContextStubWithExtensions());
            mock_context->SetGLVersionString("3.0");
            InitializeDynamicGLBindingsGL(mock_context.get());
        } else
            InitializeDynamicGLBindingsGL(context);
        break;
    default:
        return false;
    }

    return true;
}

void InitializeDebugGLBindings()
{
    InitializeDebugGLBindingsEGL();
    InitializeDebugGLBindingsGL();
    InitializeDebugGLBindingsGLX();
    InitializeDebugGLBindingsOSMESA();
}

void ClearGLBindings()
{
    ClearGLBindingsEGL();
    ClearGLBindingsGL();
    ClearGLBindingsGLX();
    ClearGLBindingsOSMESA();
    SetGLImplementation(kGLImplementationNone);

    UnloadGLNativeLibraries();
}

bool GetGLWindowSystemBindingInfo(GLWindowSystemBindingInfo* info)
{
    switch (GetGLImplementation()) {
    case kGLImplementationDesktopGL:
        return GetGLWindowSystemBindingInfoGLX(info);
    case kGLImplementationEGLGLES2:
        return GetGLWindowSystemBindingInfoEGL(info);
    default:
        return false;
    }
    return false;
}

} // namespace gfx
